The invention is generally related to the reeling of pipe and more particularly to a pipe reel load simulator.
Heretofore, there have been limited means to test the behavior of a given steel pipe line construction assembly during the pipe reeling process. Assemblies to be tested are generally joints of pipe joined by butt welding of either a single carbon steel pipe with or without some sort of elastomeric coating, or such a carbon steel pipe which is also clad internally with a corrosion resistant alloy (CRA) or a dual wall pipe assembly known as “pipe in pipe”. The means of testing specimens of these types of pipe line construction to confirm their suitability for installation by the pipe reeling process has involved simple bending tests whereby the pipe assembly specimen is either:                bent over a steel form by applying a simple shear load at the free end of the specimen, thereby causing the specimen fixed at the base of the form to be pulled into conformance with the form;        bent over a steel form by applying a simple shear load on each of the ends of the specimen; or        bent using either a simple 3-point or 4-point opposing shear load condition.        
Full scale tests can be performed using an actual pipe reeling vessel. However, such full scale tests require large amounts of specimen pipe as well as the time of costly operations of the specialized vessels used in the reeled pipeline construction business.
The reeling of steel pipe constructions involves straining the steel wall of the pipe into the plastic region. The analytical and numerical methods currently used to predict the behavior and residual integrity of a pipe construction which is reeled into its plastic limits are approximations. This is because the plastic behavior of the pipe construction during reeling is governed by the collective effects of actual material properties, precise material dimensions, and boundary loading conditions which are difficult to accurately model numerically or analytically.
In any structure loaded within its linear (non plastic) limit, the strain status is independent of the path and sequence of loading. In any nonlinear plasticity problem the status of stress and strain is highly dependent on the path and sequence of deformation patterns used to reach the status of interest. Thus, the application sequence of loads to the structure is influenced by the behavior when strained to the plastic limit.
For a physical test to provide meaningful results, the testing device must replicate as precisely as possible the actual working conditions for which the test is conceived. The current art of testing pipe construction exposed to pipe reeling strains does not accurately replicate the axial tension and the bending moment and shear loads which actually occur during the pipe reeling process. The inaccurate representation of the actual loading conditions can result in false test positives in pipe construction performance. The false test positives result in unpredicted failures during the execution of reeled pipe line construction projects, resulting in schedule delays, commercial, and possibly physical damage.
Therefore, it can be seen there is a need for a testing device that closely emulates the actual industrial process of reeling pipe to allow the validation of the designs of pipe line construction to be reeled.